Noncorrosive lubricating oil composition



Patented Aug. 7, 1956 NoNcoRRosIvE LUBRICATING OIL COMPOSITION Phillip S. Landis, Mickleton, N. J., assignor to Socony Mobil Oil Company, Inc., a corporation of New York No Drawing. Application May 14, 1953, Serial No. 355,17

4 Claims. (Cl. 25237.2)

lubricating oil compositions. it relates to a means for improving the This invention relates to More particularly,

anticorrosive character of certain lubricating oil compositions.

As is well known, it is common practice in the art to add to lubricating oils relatively small amounts of vari-- ous chemical agents designed to improve the characteristics thereof in one or more respects. Addition agents are known, for example, which inhibit oxidation of the oil in use, increase the load-carrying capacity of the oil, improve the viscosity index or lower the pour point of the oil, etc.

One type of addition agent which has been widely utilized in lubricating oils is a phosphorusand sulfur-containing product obtained by reacting phosphorus pentasulfide with an olefin or an olefinic hydrocarbon material containing a substantial proportion, i. e., upwards of about 25% by weight, of olefins. These olefins or olefinic hydrocarbons are of relatively high molecular weight, i. e., at least about 135, and preferably from about 150 to about 450, and contain from about up to about 30 carbon atoms. Such olefins are, for example, decene, dodecene, pinene, cetene, eicosene, cerotene and melene. Olefin polymers obtained by the polymerization of relatively low molecular weight olefins, preferably iso-monoolefins, such as isobutylene or of hydrocarbon mixtures containing low molecular weight olefins, such as refinery gases, cracked distillates, etc., have also been used. Mixed olefins and olefin-containing fractions, such as those produced in the vapor or liquid phase cracking of petroleum oils or waxes and olefins obtained by the dehydrohalogenation of alkyl halides, such as chlorinated paraffin wax, also are used in preparing the phosphorus pentasulfide-olefiu product additives.

Generally, the reaction between the olefinic hydrocarbon reactant and the phosphorus pentasulfide is conducted at temperatures of from about 100 C. to about 250 (1., an excess of the olefin being used. A ratio of from about 2 to about 10 moles of the olefin rectantper mole of the P285 reactant is generally suitable, a ratio of from 4 to 8 moles being preferred. The reactionis-generally completed in from about 1 to about 10 hours.

The afore-described PzSs-olefinic hydrocarbon prod-- ucts are highly effective as antioxidants in mineraljlu-.

bricating oils. Unfortunately, however, they exhibit a rather high corrosiveness towards copper. This constitutes a serious drawbackwith respect to their use'as antioxidants in oil compositions intended for use in internal combustion engines having metal parts comprising copper, such as copper-lead bearings. It is, therefore, the primary object of this invention to provide a means for inhibiting the corrosiveness towards copper of oils containing these additionagents. More specifically, it is an object of the invention to provide oil compositionsfof these addition agents which are substantially non-corrosive towards copper and which are, therefore, highly suitable for use in internal engines having copper parts.

i Other and further objects of the invention will appear from the following detailed description thereof.

In accordance with this invention, it has now been found that by incorporating zinc tallate in an oil containing an antioxidizing amount of a phosphorus pentasulfide-olefinic hydrocarbon reaction product, which amount normally causes the oil to be corrosive towards copper, the oil is made non-corrosive towards copper. More specifically, it has been found that by incorporating into the oil an amount of zinc tallate which will supply from at least parts, by weight of zinc per 1000 parts of sulfur present in the oil due to the phosphorus-sulfide-olefinic hydrocarbon product, the oil is made non-corrosive to copper.

The patent to Folda, No. 2,510,031, discloses the utility of certain metal soaps of oil-soluble organic acids for inhibiting hydrogen sulfide formation in certain types of sulfurized oils is disclosed. However, it has now been recognized that hydrogen sulfide evolution in sulfurized hydrocarbon materials and the corrosiveness of such materials towards copper are a distinct and a non-correlatable phenomena. Thus, it has been found that metal soaps which are effective in preventing hydrogen sulfide evolution in such sulfurized materials are not necessarily eifective in reducing their corrosiveness towards 'copper. It will be appreciated, therefore, that the present invention is of a distinct nature from the invention disclosed in the aforesaid Folda patent, as will be evident from the following examples and test results which illustrate the present invention.

ZINC TALLATE The zinc tallate utilized in the following examples was prepared as follows: Fifteen hundred grams of process oil (a parafin oil having a Saybolt Universal viscosity of 106 seconds at F. and 40 seconds at 210 F.) and 1500 grams of Facoil CS, a solvent-refined tall oil comprising about 50% fattyacids and 45% rosin acids and having an acid number of'160180 and an iodine number of -170, were reacted with 200 grams of zinc oxide at a temperature of approximately C. for two hours in a five-liter flask using a nitrogen atmosphere, stirring and a water take-01f device. Water (32 ml.) was removed from the reaction and the product filtered by suction, 3110 grams of the product being thus ob: tained. This product (a 50% oil solution of zinc tallate) analyzed 5.3% zinc.

COPPER CORROSION TEST The test used in all of the examples herein was the copper strip test. This test is a specification test commonly used in determining whether or not an oil will attack and corrode the copper parts of an engine, such as the bearings. In this test, a bright copper strip is immersed in the test oil while the oil is maintained at a temperature of 212 F. for a period of 24 hours. A pass requires that the copper strip remain entirely free from discoloration or stain in the course of the test.

, Example I PaSa-DODECENE-l REACTION PRODUCT A'hypical phosphorus sulfide-olefinic hydrocarbon retest. However, after addition to the blend of I 0.35%

100 parts, preferably from 100 to 200,

P2S -OLEFiI-N FRACTION REACTION PRODUCT Eight moles of anolefinic hydrocarbon fraction (obtained from the vapor phasecrackingof a waxy oil stock), consisting of 97% olefins' and having a bromine number of 86, a distillation range of 196 to 273 C., and a molecular weight of 180, was reacted with 1 mole of P255 at 145 C. for 3' hours with stirring whilethe reactants were kept under nitrogen atmosphere. The resulting product was topped at 4 to 5 mm. pressure and. gave 279 grams of distillate (recovered olefin) and 212 grams of residue. This residue contained 8.1% phosphorus and 21.2% sulfur.

A. 1% blend of this product (residue) in a solventrefined paraffinic oil having a Saybolt Universal viscosity of 185 to 195 seconds at 100 F. gave a heavy gray coating to the copper in'the copper strip test. However, the

' same 1% blend, after-addition of 0.5% zinc tallate (125 parts of zinc per 1000 parts of sulfur due to. the phosphorus sulfide-olefin product) gave a bright copper strip in the copper strip test.

Example Ill P2S -POLYMER GASOLINE REACTION PRODUCT Seven hundred and twenty grams (3.6 moles) of heavy (I) 2.0% calcium tallate (180 parts of calcium per 1000 parts'of sulfur. supplied by the PzSs-dodecene-l reaction product).

(J) 2.0% magnesium linoleate (240 parts of mag nesium per 1000 parts of sulfur supplied by the P255- do'decene-l reaction product).

(K) 1.0% barium n'aphthenate (225 parts of barium per 1000 parts of sulfur supplied by the PzSs-dodecene-l reaction product).

The resulting blends, A, B, C, D, E, F, G, H, I, I and K, and the 1% PzSa-dodcene-l reaction product blend were subjected to copper strip tests, the results of which are summarized in the accompanying table.

. Parts Metal 011 Blend Cop er Strip Test at 1,000 Q PParts s 24 firs. 212 F.

- 1% Pzss-Dodeeene-l Product-.- None Fail (Black Cu).

A. (Zn Tallate 75 Fail (Lt. Purple Cu). B. (Zn Tallate). 100 Pass (Bright Cu).

6. (.Zn Tallate). 200 0. D. (Pb Naphthenate) 100 Fail (Black Cu).

E. (Pb Naphthenate). 200 Do.

F. (Cu Naphthenate 100 D0.

G (Cu Naphthenate) 200 Fall.(Browu Cu).

B ECd Tallate) 200 Fail (Purple G11).

I. 7 Ge; Tallate).-- 180 Do.

J. (Mg Linoleate) 240 Do.

K. (Ba Naphthenate) 225 o.

polymer gasoline, supplied by the Pan American Refining Co., having a molecular weight of 200, a bromine number of 121 and a boiling range of 176 to 333 C. were reacted with 66.6 grams (0.3 mole) of P285 at 190 to 200 C. for 6 hours. The product was vacuum distilled to 150 C. at -1 mm. and gave 490 grams of. distillate and 260' grams of residue. The residue contained 7.0% phosphorus and 16% sulfur.

A 1% blend of the product (residue) in a solvent-refined paraflinic oil having a Saybolt'Universal viscosity of 185 to 195 seconds at 100 F. gave a black strip in the copper.

strip test. However, this blend, upon addition to 0.5% zinc tallate (165 parts of zinc per 1000 parts of sulfur supplied by the phosphorus pentasulfide polymer gasoline product) gave a bright copper strip in the copper strip test.

Examples 'l(A)-I(K) Utilizing the 1% blend of PzSs-dodecene-l reaction product used in Example I, the following series of test blends were prepared. To separate portions of the aforesaid blend there was added the following:

(A) 0.27% zinc tallate. 75 parts of zinc per 1000 parts of sulfur supplied by the PzSs-dudecene-l reaction prodnot).

(B) 0.35% Zinc tallate (100 parts of zinc. per 1000 parts of sulfur supplied by the Pzss-dodecene-l reaction product).

(C) 0.70% zinc tallate (200 parts of zinc per 1000 parts of sulfur supplied by the PzSs-dodecene-l reaction product).

(D) 0.07% lead naphthenate (100 parts of lead per 1000 parts of sulfur supplied by the PzSs-dod'ecene-l reaction product).

(E) 0.14% lead naphthenate (200 parts of lead per 1000 parts of sulfur supplied by the PzSs-dodecene-l reaction product).

(F) 0.22% copper naphthenate (100 parts of copper per 1000 parts of sulfur supplied by the PzS's-dodecene-l reaction product).

(G) 0.44% copper naphthenate (200 parts of copper per 1000 parts of sulfur supplied by' the PzSs-dodecene-l reaction product).

(H) 0.5% cadmium tallate (200 parts of cadmium. per 1000 parts of sulfur supplied by the PzSs-dodecene-l reaction product).

Examples I(A)I(K) illustrate the distinction between the problem. of'in'hibiting copper corrosion by the phos- 'phorus pen-tasulfide-olefinic hydrocarbon product additives and the problem of inhibiting hydrogen sulfide evolution copper corrosion when utilized in the amounts taught by Folda. Furthermore, it is seen that these, as wellas a number o other soaps tested, including cadmium .tallate, are not effective for this. purpose even in amounts of or even 200 parts of. metal: per 1000 parts of sulfur in the oil. Zinc tallate is. also ineffective in the amounts. taught by Folda, however, it is completely efiective in amounts of 100, or more, parts of zinc per 1000 parts of sulfur in the oil. It is considered that theunique efiectiveness thus shown by the zinc tallate. clearly distinguishes the present invention from that of Folda.

The amount of phosphorus pentasulfide-olefinic hydrocarbon. reaction product generally utilized as an antioxidant in lubricating oil. ranges from. about 0.5 to about 10%,. by weight, the usual. required amount being about 1 or 2%. The zinc tallate is contemplated. for use in the oil along with these amounts of the antioxidant.

Other additives may also be used in. the oil in conjunction with the additive combination herein defined, such as detergents, pour depressants, viscosity index improvers, extreme pressure agents, antirust inhibitors, etc.

Although the invention has been described herein by way of certain specific examples, it is to be understood that such examples are. illustrative only and that the scope of the invention is to be. limited. only by the appended claims.

What is claimed is:

1. A mineral lubricating oilucontaining (a) a minor proportion, sufiicient to inhibit oxidation of said oil, of a phosphorus.- and sulfur-containing reaction product formed by reacting 1 mole of phosphorus pentasulfide with from about 2 to about 10 moles of an olefinic hydrocarbon material having a molecular. weight of from at least about up to about 450 and containing upwards of about. 25% olefins, at a temperature of from about 100 C'. to about 250 C. and for a time period of from about. 1 to about 10 hours, and (b) zinc tallate, in an amount to supply to the oil from 100 to 200 parts of zinc per 1000 parts of sulfur present in the oil due to said phosphorusand sulfur-containing reaction product.

2. A mineral lubricating oil containing (a) a minor proportion, suflicient to inhibit oxidation of said oil, of a phosphorusand sulfur-containing reaction product formed by reacting 1 mole of phosphorus pentasulfide with from about 2 to about 10 moles of dodecene-l, at a temperature of from about 100 C. to about 250 C. and for a time period of from about 1 to about 10 hours, and (b) zinc tallate, in an amount to supply from 100 to 200 parts of zinc per 1000 parts of sulfur present in the oil due to said phosphorusand sulfur-containing reaction product. 3. A mineral lubricating oil containing (a) a minor proportion, sufficient to inhibit oxidation of said oil, of a phosphorusand sulfur-containing reaction product formed by reacting 1 mole of phosphorus pentasulfide with from about 2 to about 10 moles of an olefinic hydrocarbon fraction, obtained from the vapor-phase cracking of a Waxy oil stock, said olefinic fraction comprising about 97% olefins and having a bromine number of about 86, a distillation range of about 196 C. to about 273 C. and a molecular weight of about 180, at a temperature of from about 100 C. to about 250 C. and for a time period of from about 1 to about 10hours, and (b) zinc tallate,

in an amount to supply from 100 to,.200 parts of zincper 1000 parts of sulfur present in the oil due to said phosphorusand sulfur-containing reaction'product.

4. A mineral lubricating oil containing (a) a minor proportion, suflicient to inhibit oxidation of said oil, of

a phosphorusand sulfur-containing reaction productformed by reacting 1 mole of phosphorus pentasulfide with from about 2 to about 10 moles of a polymer gasoline,

said gasoline having a bromine number of about 121, a.

distillation range of from about 176 C. to about 333 C. and a molecular weight of about 200, at a temperature of from about 100 C. to about 250 C. and for a time .period of from about 1 to about 10 hours, and' (b) zinc References Cited in the file of this patent UNITED STATES PATENTS Morway Mar. 1, 1938 Nill May 16, 1944 

1. A METALLIC LUBRICATING OIL CONTAINING (A) A MINOR PROPORTION, SUFFICIENT TO INHIBIT OXIDATION OF SAID OIL, OF A PHOSPHORUS- AND SULFUR-CONTAINING REACTION PRODUCT FORMED BY REACTING 1 MOLE OF PHOSPHORUS PENTASULFIDE WITH FROM ABOUT 2 TO ABOUT 10 MOLES OF AN OLEFINIC HYDROCARBON MATERIAL HAVING A MOLECULAR WEIGHT OF FROM AT LEAST ABOUT 135 UP TO ABOUT 450 AND CONTAINING UPWARDS OF ABOUT 25% OLEFINS, AT A TEMPERATURE OF FROM ABOUT 100* C. TO ABOUT 250* C. AND FOR A TIME PERIOD OF FROM ABOUT 1 TO ABOUT 10 HOURS, AND (B) ZINC TALLATE, IN AN AMOUNT TO SUPPLY TO THE OIL FROM 100 TO 200 PARTS OF ZINC PER 1000 PARTS OF SULFUR PRESENT IN THE OIL DUE TO SAID PHOSPHORUS- AND SULFUR-CONTAINING REACTION PRODUCT. 